3.3. How do I store chemicals?
Description
This article is from the Darkroom
Work FAQ, by Cees de Groot
3.3. How do I store chemicals?
A discussion that is coming up over and over again is what kind of bottles are best used to store chemicals. The best stuff, but you already knew that, is dark brown glass bottles with stops made for keeping chemicals in and air out. Glass doesn't let air through and is easy to clean, and these are the two most important considerations (brown glass also doesn't let light in that could harm your chemicals). These bottles are also the most expensive ones, so you might want to use them only for chemicals that oxidize easily, like developer.
Plastics are permeable to air, and not as easy to clean (chemicals can and will be absorbed by plastic and it'll never get out). The cleaning part is solved mostly by only using any given container for a single type of solution. How much oxygen can get to your chemicals depends on the type of plastic and its thickness (the thicker, the better). The best solution is metalized plastic, then PETE, HDPE, LDPE, PP, PVC, PS and last and worst Teflon. Here's an overview of plastics names, the numbers that appear inside the "recycling triangle" on containers from these materials, and what they're often used for:
1 Polyethylene terepthalate (PETE) soft drink bottles 2 High Density Polyethylene (HDPE) milk, juice and laundry product bottles, Nalgene laboratory ware and bottles 3 Polyvinyl Chloride (PVC) cooking oil, water, vinegar and bleach bottles 4 Low Density Polyethylene (LDPE) bags, margarine and ice containers 5 Polypropylene (PP) yogurt cups and ketchup and syrup bottles 6 Polystyrene (PS) clear: salad containers, disposable cups; expanded: insulating food containers - (Poly)tetrafluoroethylene ((P)TFE) Dupont Trademark "Teflon"; laboratory and environmental sampling containers
(table and most of the information in this section from a posting by Marc Hult <mailto:hult@cinternet.net> in rec.photo.darkroom, Message ID <35545554.231656@news.one.net>).
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